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The Franck–Hertz Experiment
Published in Robert E. Robson, Ronald D. White, Malte Hildebrandt, Fundamentals of Charged Particle Transport in Gases and Condensed Matter, 2017
Robert E. Robson, Ronald D. White, Malte Hildebrandt
These calculations include the effect of elastic collisions through the momentum transfer cross section σm. While this is clearly enormous (note the different scales in Figure 16.3), the traditional discussion ignores such collisions entirely, that is, σm=0, but still gets the right result, if the other inelastic processes are ignored. How can this be?
Scattering of e± from N2 in the energy range 1 eV–10 keV
Published in Molecular Physics, 2020
Mahmudul H. Khandker, Nazifa T. Arony, A. K. F. Haque, M. Maaza, M. Masum Billah, M. Alfaz Uddin
The spin-polarisation during the scattering of electron and positron requires the inclusion of spin-orbit interaction term in the Schrödinger equation. On the other hand, this term is simply incorporated in Dirac's relativistic equation. McEacharan and Stauffer [7] carried out relativistic calculations on the momentum transfer cross section, scattering length and differential cross sections at low energies for the electron-argon scattering. The results produced an excellent agreement with experiments and showed an improvement over the non-relativistic analysis. Encouraged by the above facts, we adopt Dirac partial wave analysis, with complex atomic OPM, to calculate differential cross section (DCS), integrated elastic cross section (IECS), momentum transfer cross section (MTCS), viscosity cross section (VCS), inelastic cross section (INCS), total cross section (TCS) and total ionisation cross section (TICS) for the scattering of electron and positron from nitrogen atom. Then sums of these cross sections of the individual atoms are taken to produce corresponding molecular cross sections. These cross sections obtained in this simplistic way of AR are used for modelling codes for various applications as stated above.
Elastic scattering of e∓ by Na atoms
Published in Molecular Physics, 2018
M. Elias Hosain, M. Atiqur R. Patoary, M. M. Haque, A. K. Fazlul Haque, M. Ismail Hossain, M. Alfaz Uddin, Arun K. Basak, M. Maaza, Bidhan C. Saha
For both elastic and inelastic scattering of electrons from Na atoms, Srivastava and Vukovi [7] measured the absolute DCS at energies 10, 20, 40 and 54.4 eV and scattering angles ranging from 10 ° to 120 °. They also computed the total integrated elastic cross-section (IECS) and the momentum transfer cross-section (MTCS) using their measured DCS results. Teubner et a1. [8] have reported inelastic DCS over the angular range 2 ° ≤θ ≤ 130 ° at incident electron energies of 22.1 and 54.4 eV. Elastic DCSs have been measured at E = 54.4 eV by Allen et al. [9] for their first reported application of the complex phase-shift technique in the analysis of the data. They have also presented TCS derived from their DCS. Jiang et al. [10] have measured the absolute DCS for the scattering of 10 eV electrons by the ground-state Na atoms. Recently, spin-resolved super-elastic electron scattering from Na atoms has been measured by Scholten et al. [11] and they also reported DCS and MTCS. On comparing the experimental e−–Na scattering cross-sections, it is observed that the findings of [7] disagree with those due to [5,6]. The experimental outcome of [4], on the other hand, agree closely with those of [6] but disagreement remains with the results due to [7].
Relativistic treatment of scattering of electrons and positrons by mercury atoms
Published in Molecular Physics, 2019
M. M. Haque, A. K. F. Haque, Prajna P. Bhattacharjee, M. Alfaz Uddin, M. Atiqur R. Patoary, A. K. Basak, M. Maaza, B. C. Saha
The elastic differential cross-section (DCS) and the integrated elastic cross-section (IECS) are given respectively by and The momentum transfer cross-section (MTCS) is and viscosity cross-section (VCS) is given by The grand total cross-section (TCS), the sum of the total elastic and absorption cross-sections, is determined from the equation where, Im denotes the imaginary part of the expression that follows and f(0) denotes the direct scattering amplitude in the forward direction.